the potential energy surface of gaseous glycine determined years ago in the ab initio b3lyp/6-311++g** calculations is composed of thirteen stable conformers. we performed the ab initiomolecular orbital calculations as the starting point to carry out a force field and normal coordinatecalculation on the most stable conformer of non-zwitterionic glycine [conformer (i)]. thecalculations were carr...

A translationally invariant form ulation ofthe Hartree-Fock (HF) -point approxim ation is presented.Thisform ulation isachieved through introduction oftheM inim um Im ageConvention (M IC) atthe levelofprim itive two-electron integrals,and im plem ented in a periodic version ofthe O NX algorithm [J.Chem .Phys,106 9708 (1997)]for linear scaling com putation ofthe exchange m atrix.Convergence ofth...

Nowadays NMR spectroscopy becomes a powerful tool in chemistry because of the NMR chemical shifts. Hartree–Fock theory and the Gauge-including atomic orbital (GIAO) methods are used in the calculation of 29Si NMR chemical shifts of various silicate species in the silicate solution as initial components for zeolite synthesis both in gas and solution phase. Calculations have been performed at geo...

In this study, paraphenylenediamine was first bonded to the fullerene and was optimized geometrically by Using the quantum chemistry methods. paraphenylenediamine was examined in the isolated state and in the fullerene-bonded state via carbon atoms. In the theoretical research, the simulation was done by the Gauss View software. Then, the bonding orbital calculation was done by using the NBO me...

DPPC (dipalmitoylphosphatidylcholine) and DMPC (dimyristoylphosphatidylcholine) are taken asphospholipids with an equal polar heads and with the difference in the length of hydrocarbonchains. Results obtain from the structural optimization of the isolated DPPC and DMPC in the gasphase, at the Hartree-Fock level of theory by means of STO-3g,3-21G, 6-31G and 6-31G* basissets. the most important d...

ABSTRACT: Hamiltonian and Schrödinger evolution equations on finitedimensional projective space are analyzed in detail. Hartree-Fock (HF) manifold is introduced as a submanifold of many electron projective space of states. Evolution equations, exact and linearized, on this manifold are studied. Comparison of matrices of linearized Schrödinger equations on many electron projective space and on t...

Few-electron systems confined in two-dimensional parabolic quantum dots at high magnetic fields are studied by the Hartree-Fock (HF) and exact diagonalization methods. A generalized multicenter Gaussian basis is proposed in the HF method. A comparison of the HF and exact results allows us to discuss the relevance of the symmetry of the charge density distribution for the accuracy of the HF meth...

Inhibition performances of imidazoline derivatives with different alkyl chain length for carbon steel in H2S acid solutions has been studied by polarization curves, AC impedance measurements, current transient, Atomic Force Microscopy (AFM) and Density Functional Theory (DFT) techniques. Results showed that the inhibition occurs through adsorption of the inhibitors molecules ...

The impact of Hartree-Fock correlations on the nuclear momentum distribution is studied in a fully relativistic one-boson-exchange model. Hartree-Fock equations are exactly solved to first order in the coupling constants. The renormalization of the Dirac spinors in the medium is shown to affect the momentum distribution, as opposed to what happens in the non-relativistic case. The unitarity of ...

We calculate ground state energies in the Brueckner-Hartree-Fock theory for N electrons with N 20 confined to a circular quantum dot and in presence of a static magnetic field. Comparison with the predictions of Hartree-Fock, local-spin-density and exact configuration-interaction theories is made. We find that the correlations taken into account in Brueckner-Hartree-Fock calculations give an im...